High-power-density speed reducer connecting structure

A high-power-density speed reducer connecting structure relates to the technical field of speed reducers and comprises a connecting flange and a connecting shaft, wherein the outer edges of the two end faces of the connecting flange can be detachably and fixedly connected with a speed reducer input end flange and a motor output end flange respectively, and one end of the connecting shaft can be in transmission connection with a speed reducer input shaft. An inner hole of the key sleeve can be inserted and matched with a corresponding motor output shaft; the other end of the connecting shaft is coaxially and rotatably inserted into a central through hole of the connecting flange, and is axially and radially positioned with the connecting flange; the center of the end face of the shaft end, close to the motor, of the connecting shaft is provided with a blind hole allowing the key sleeve to be inserted therein, the inner wall of the blind hole and the outer wall of the key sleeve are circumferentially positioned